Process for preparing a sulphur cement product

Abstract

The invention provides a process for preparing a sulphur cement product comprising the following steps: (a) selectively oxidising hydrogen sulphide to elemental sulphur by contacting, in a reaction zone, a hydrogen sulphide containing feed gas and a molecular-oxygen containing gas with a particulate oxidation catalyst under selective oxidation conditions; (b) discharging a stream comprising liquid and/or solid elemental sulphur and particulate oxidation catalyst from the reaction zone; (c) admixing the stream comprising elemental sulphur and particulate oxidation catalyst with at least any one of elemental sulphur, a sulphur cement filler, a sulphur cement modifier, or aggregate at a temperature at which sulphur is molten; (d) solidifying the mixture obtained in step (c) by cooling it to a temperature below the melting temperature of sulphur to obtain the sulphur cement product. The invention further provides the use of a stream comprising elemental sulphur and particulate oxidation catalyst for preparing a sulphur cement product, which stream is obtained in selective oxidation step (a) of such process.

1. A process for preparing a sulphur cement product, comprising the following steps:
 (a) selectively oxidising hydrogen sulphide to elemental sulphur by contacting, in a reaction zone, a hydrogen sulphide containing feed gas and a molecular-oxygen containing gas with a particulate oxidation catalyst under selective oxidation conditions; 
 (b) discharging a stream comprising liquid and/or solid elemental sulphur and particulate oxidation catalyst from the reaction zone; 
 (c) admixing the stream comprising elemental sulphur and particulate oxidation catalyst with at least one of elemental sulphur, a sulphur cement filler, a sulphur cement modifier, or aggregate at a temperature at which sulphur is molten; 
 (d) solidifying the mixture obtained in step (c) by cooling it to a temperature below the melting temperature of sulphur to obtain the sulphur cement product. 
 
     
     
       2. A process according to  claim 1 , wherein the sulphur cement product is selected from the group consisting of a sulphur cement premix composition, a sulphur cement, and a sulphur cement-aggregate composite. 
     
     
       3. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst at a temperature at which the elemental sulphur formed is liquid. 
     
     
       4. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst in the presence of an inert liquid medium. 
     
     
       5. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst in a slurry bubble column. 
     
     
       6. A process according to  claim 1 , wherein the particulate oxidation catalyst comprises an oxide and/or sulphide compound of a metal. 
     
     
       7. A process according to  claim 1 , wherein the hydrogen sulphide containing feed gas comprises hydrogen sulphide in a concentration in the range of from 0.5 to 50 volume %. 
     
     
       8. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst at a pressure in the range of from 2 to 200 bar (absolute). 
     
     
       9. A process according to  claim 1 , wherein the stream comprising elemental sulphur and particulate oxidation catalyst discharged from the selective oxidation reaction zone comprises particulate oxidation catalyst in a concentration in the range of from 2 to 50 wt %, and comprises elemental sulphur in a concentration in the range of from 50 to 98 wt %. 
     
     
       10. A process according to  claim 1 , wherein the particulate oxidation catalyst is in the form of particles having an average diameter in the range of from 0.2 to 100 μm. 
     
     
       11. A process according to  claim 1 , wherein the temperature in step (c) is in the range of from 110 to 180° C. 
     
     
       12. Use of the stream comprising elemental sulphur and particulate oxidation catalyst that is obtained in a selective oxidation process as defined in step (a) of the process according to  claim 1  to prepare a sulphur cement product. 
     
     
       13. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst at a temperature in the range of from 110 to 180° C. 
     
     
       14. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst at a temperature in the range of from 125 to 150° C. 
     
     
       15. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst in the presence of elemental sulphur as inert liquid medium. 
     
     
       16. A process according to  claim 1 , wherein the particulate oxidation catalyst comprises an oxide and/or sulphide compound of iron. 
     
     
       17. A process according to  claim 1 , wherein the particulate oxidation catalyst comprises a hydrated oxide compound of iron. 
     
     
       18. A process according to  claim 1 , wherein the hydrogen sulphide containing feed gas comprises hydrogen sulphide in a concentration in the range of from 1 to 25 volume %. 
     
     
       19. A process according to  claim 1 , wherein in selective oxidation step (a) the hydrogen sulphide containing feed gas and the molecular-oxygen containing gas are contacted with the catalyst at a pressure in the range of from 10 to 150 bar (absolute). 
     
     
       20. A process according to  claim 1 , wherein the stream comprising elemental sulphur and particulate oxidation catalyst discharged from the selective oxidation reaction zone comprises particulate oxidation catalyst in a concentration in the range of from 5 to 35 wt %, and comprises elemental sulphur in a concentration in the range of from 65 to 95 wt %.